![]() Relatives of this newly identified toothy animal would give rise to two of the major groups of modern fish – chondrichthyans (sharks and rays) as well as osteichthyans which include almost everything else from seahorses and tuna to lungfish. Little more than heavily modified fish gills, they can still be found in more than 99 percent of today's vertebrates. Jaws are clearly one of the success stories of the animal kingdom. ![]() This helped early backboned animals move into new environments which continued to shape their anatomy, leading to the huge diversity of body shapes and different behaviors we see in vertebrates today. The development of jaws was a pivotal innovation in the evolution of vertebrates, giving boned animals like ourselves the ability to eat a much larger variety of foods than our ancestors' filter-feeding mouths would allow. Left by an ancient fish species called Qianodus duplicis, they give us our earliest look at the origins of our very own teeth and jaw. A collection of about 20 teeth sifted from the rock bed could be up to 439 million years old. Previously, the earliest known jawed animal was a fish that lived some 423 million years ago. ![]() ![]() "Until this point, we've picked up hints from fossil scales that the evolution of jawed fish occurred much earlier in the fossil record, but have not uncovered anything definite in the form of fossil teeth or fin spines," says University of Birmingham paleobiologist Ivan Sansom. ![]()
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